JP3036606B2 - Image reading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for reading an image on a color film or the like to obtain a video signal.

[0002]

2. Description of the Related Art According to an image reading device such as an image scanner or a film scanner, a video signal can be obtained by reading an image printed on paper or the like or an image on a color film.

First, an example of such an image reading apparatus will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes an image to be read. In this example, a 35 mm reversal film is used for simplicity. Reference numeral 20 denotes a microcomputer that comprehensively controls the operation or processing of each unit of the device, reference numeral 30 denotes a clock forming circuit that forms clocks of various timings, reference numeral 50 denotes a memory controller,
The controller 50 includes memories 15R to 15
A circuit for forming a write address signal for B and a circuit for forming a read address signal (both not shown).

Then, white light from the light source 2 is applied to the film 1 through the color separation filter 3, and an image of the film 1 is formed on the line sensor 11 by the imaging lens 4. In this case, the film 1 is moved by the driving motor 21 at a predetermined speed in the horizontal direction H (sub-scanning direction) at the time of imaging. Further, the color separation filter 3 includes a filter unit that transmits the three primary color lights, that is, a filter unit R that transmits the red light, a filter unit G that transmits the green light, and a filter unit B that transmits the blue light. And the filter units R and B are rotated by the drive motor 23 so that the light source 2 and the film 1
And on the optical path between them.

Further, the line sensor 11
It has a large number of photosensor sections corresponding to the number of pixels in the (main scanning direction) and is provided at the image forming position of the lens 4 so that the arrangement direction is the vertical direction V. The read clock RDCK is supplied.

Reference numeral 12 denotes a gain control amplifier, 13 denotes a gamma correction amplifier, 14 denotes, for example, an 8-bit A / D converter, and 15R to 15B denote frame memories. And
The gamma correction amplifier 13 performs an optimum gamma correction corresponding to a case where the read image 1 is a reversal film, a negative film, a general document, or the like. It is controlled by a control signal. In addition, the frame memories 15R to 15B
For example, the memory is a dual-port memory having an output line buffer, and a write address signal and a read address signal (and a write / read control signal) are supplied from the memory controller 50.

Reference numerals 16R to 16B denote look-up tables, 17R to 17B denote D / A converters, and 18 denotes a matrix circuit. In this case, the look-up tables 16R to 16B are for correcting the hue and the gradation in accordance with the type of the image to be read 1 and the like.
The content of the correction is controlled by the microcomputer 20. Further, the matrix circuit 18 is for forming a luminance signal and a color difference signal from the three primary color signals.

The reading of the film 1 is performed as follows. That is, the motor 23 is controlled by the microcomputer 20, and the red filter portion R of the color separation filter 3 is located on the optical path between the light source 2 and the film 1.
Subsequently, the motor 21 is controlled by the microcomputer 20, the film 1 is transferred at a predetermined speed in the horizontal direction H for a target frame , and the read clock RDCK is supplied from the forming circuit 30 to the line sensor 11. .

Therefore, from the line sensor 11, an image signal S11 of a red component of a target frame of the film 1 is extracted at a speed corresponding to the moving speed of the film 1 and the frequency of the read clock RDCK.

The signal S11 of the red component is supplied to an A / D converter 14 through an amplifier 12 and a gamma correction amplifier 13 and A / D converted into a digital red signal R14. The signal R14 is sequentially stored in a frame memory 15R. Written. Note that the write address at this time is an address corresponding to the vertical and horizontal scanning positions of the line sensor 11. That is, as indicated by an arrow in FIG. 5A, the write address is incremented by one pixel in the vertical scanning direction, and is incremented by one pixel in the horizontal scanning direction each time one vertical scanning is completed (memory). It is assumed that the address of 15R increases in the horizontal scanning direction and further in the vertical scanning direction every horizontal scanning.

In this way, the target frame of the film 1 is imaged by the line sensor 11, and the red signal R14 for one frame is stored in the frame memory 15R.

Next, the color separation filter 3 is
Green filter section G is positioned on the optical path between the light source 2 and the film 1, and
The film 1 moves in the horizontal direction H at a predetermined speed
Is transferred to

Therefore, an image signal S11 of a green component of a target frame of the film 1 is taken out from the line sensor 11, and the A / D converter 14 A / D converts the signal S11 into a digital green signal G14. This signal G
14 are sequentially written to the frame memory 15G. Thus, the green signal G14 for one frame of the target frame of the film 1 is stored in the frame memory 15G.

Subsequently, the blue filter portion B of the color separation filter 3 is positioned on the optical path between the light source 2 and the film 1 by the motor 23, and the film 21 is moved by the motor 21 to a predetermined frame. At the speed of the horizontal direction H.

[0016] Thus, from the line sensor 11, the imaging signal S11 of the blue component of the frame of interest of the film 1 is taken out, the signal S11 is A / D converted into a digital blue signal B14 by the A / D converter 14, This signal B
14 are sequentially written to the frame memory 15B. Thus, the blue signal B14 for one frame of the target frame of the film 1 is stored in the frame memory 15B.

Thus, the purpose of the film 1 isFrame
Are in the order of plane by the color separation filter 3 and the line sensor 11
Next, an image is taken, and the digital color signals R14 to B14 are
Is stored in each of the memory memories 15R to 15B.

Subsequently, or at the same time as writing to the memories 15R to 15B,
Reading is performed. In this case, as shown by an arrow in FIG. 5B, for example, the read address is incremented by one pixel in the horizontal scanning direction, and
Each time the horizontal scanning is completed, the pixel is incremented by two pixels (two lines) in the vertical scanning direction. The reading speed at this time corresponds to the synchronization speed of the NTSC system or the PAL system, and this reading is repeated every frame. Therefore, from the memories 15R to 15B, the digital color signals R15 to R15 of the synchronous speed in the NTSC system or the PAL system are read.
B15 is taken out.

The signals R15 to B15 are supplied to the D / A converter 1 through the look-up tables 16R to 16B.
7R to 17B and D / A converted to analog color signals R17 to B17. The signals R17 to B17 are supplied to a matrix circuit 18 and output terminals 19Y, 19R, and 19B.
Then, a luminance signal Y18 and red and blue color difference signals R18 and B18 in the NTSC system or the PAL system are extracted.

Therefore, these signals Y18 to B18 are
When supplied to an RT display (television receiver), the image on the film 1 is displayed.

The signals R from the memories 15R to 15B
At the time of reading 15 to B15, as shown by the arrow in FIG. 5C, the read address is decremented by one pixel in the vertical scanning direction, and every time one vertical scanning is completed, two pixels are read out in the horizontal scanning direction. , The image of the film 1 is displayed in a state of being rotated clockwise by 90 °. Alternatively, as shown by an arrow in FIG. 5D, if the read address is incremented by one pixel in the vertical scanning direction and decremented by two pixels in the horizontal scanning direction each time one vertical scanning is completed,
The image on the film 1 is displayed in a state where it is rotated 90 ° counterclockwise.

The above is the general configuration and operation of the image reading apparatus. Hereinafter, a display image that is not rotated by 90 ° is referred to as an “erect image”.

[0023]

Generally, in digital video equipment, the sampling frequency (quantization frequency) of a video signal is selected to be four times the color subcarrier frequency. For this reason, in the image reading apparatus as described above, the sampling frequency of the signals R15 to B15 supplied to the A / D converters 17R to 17B is set to be four times the color sub-carrier frequency. Then, when the output signals Y18 to B18 are of the NTSC system, the number of pixels effectively displayed on the display screen and the number of pixels in the blanking period have values as shown in FIG.
In the case of the L system, the values are as shown in FIG. 6B.

However, the common memories 15R to 15B have the same number of pixels as shown in FIG. 6A in the case of the NTSC mode, and FIG. 6B in the case of the PAL mode. In order to read out the signals R15 to B15 so that the number of pixels becomes as shown in FIG. 14, it is necessary to perform interpolation or thinning on the signals R15 to B15 read out from the memories 15R to 15B in accordance with the readout mode.
Therefore, a circuit for forming the read address signal for the memories 15R to 15B becomes very complicated.

Further, when the display image is displayed in a state rotated by 90 °, the read addresses of the memories 15R to 15B must be changed as shown in FIGS. 5C and 5D. Becomes even more complicated.

Moreover, the reading must be performed at a high speed corresponding to the synchronization speed of the NTSC system or the PAL system. Therefore, a circuit for forming a read address signal for the memories 15R to 15B becomes more expensive due to a higher speed.

The present invention is intended to solve such a problem.

[0028]

Therefore, according to the present invention, in the image reading apparatus using the line sensor 11, the read clock RDCK of the line sensor 11 is set to correspond to the embodiment described later. A supplied PLL 64 and a variable frequency dividing circuit 66 for dividing the output signal S62 of the PLL 64 are provided.

The output signal S66 of the variable frequency dividing circuit 66 for dividing the frequency of the output signal S62 of the PLL 64 is converted to the A / D converter 14
The output signal S of the variable frequency dividing circuit 66 for dividing the frequency of the output signal S62 of the PLL 64
66, write address signals for the memories 15R to 15B are formed and supplied to the memories 15R to 15B, and correspond to the format of the output video signals R18 to B18 and the direction of the image displayed by the video signals Y18 to B18. hand,
Write address signal and two variable frequency dividing circuits 63, 6
6 and the memory 15R.
15B to 15B, a read address signal which changes in accordance with the format of the output video signals Y18 to B18 is supplied to obtain the video signals Y18 to B18.

[0030]

The read address signals for the memories 15R to 15B only relate to the format of the output video signals Y18 to B18.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the entire circuit is configured as shown in FIG. However, in this example, C CD
The line sensor 11 has a photo sensor unit for 2048 pixels.

FIG. 2 shows a part of the clock forming circuit 30.
One read clock RDCK is formed, and this read clock RDCK is supplied to the line sensor 11. In this case, the frequency f31 of the read clock RDCK is, for example,
It is assumed to be 1.2 MHz.

Further, the read clock RDCK is also supplied to the phase comparison circuit 61. This comparison circuit 61
A PLL 64 is formed together with the CO 62 and the variable frequency dividing circuit 63. An oscillation signal S62 having a frequency of Nf31 is extracted from the VCO 62, and the signal S62 is divided by the frequency dividing circuit 63.
The signal is frequency-divided into a signal having a frequency of 1 / N, that is, a signal having a frequency f31. The frequency-divided signal is supplied to a comparison circuit 61, and the comparison output is supplied to a VCO 62 as a control signal.

Further, the signal S62 from the VCO 62 is supplied to a frequency dividing circuit 65 to be frequency-divided into a signal S65 having a frequency of 1/8, and this signal S65 is supplied to a variable frequency dividing circuit 66 to produce a 1 / M signal. The frequency is divided into a signal S66 of a frequency f66, that is, f66 = N · f31 / (8M), and this signal S66 is supplied to the A / D converter 14 as a clock for the A / D conversion. The signal S66 is also supplied to the memory controller 50 as a clock for forming a write address signal. The dividing ratios N and M of the dividing circuits 63 and 66 are
It is controlled by the microcomputer 20 as described below.

Further, the controller 15 sends the memory 15
A read address signal is supplied to R to 15B, regardless of whether the displayed image is an erect image or an image rotated by 90 °.
As shown by the arrow in FIG. 3D, the read address is
It is incremented by one pixel in the horizontal scanning direction, and is incremented by two pixels in the vertical scanning direction each time one horizontal scanning is completed. The synchronization speed of the read address signal is determined by the terminals 19Y to 19Y.
The video signal extracted from 9B has a speed corresponding to the system (NTSC system or PAL system).

Then, the frequency dividing ratios N of the frequency dividing circuits 63 and 66,
M is controlled by the microcomputer 20 as follows in accordance with the mode of the NTSC system and the mode of the PAL system, and in accordance with the erect image and the image rotated by 90 °. When displaying an upright image in the NTSC system. In this case, N = 8 and M = 4. FIG.
As indicated by the arrow in A, the write address for the memories 15R to 15B is incremented by one pixel in the vertical scanning direction, and is incremented by one pixel in the horizontal scanning direction each time one vertical scanning is completed.

According to such writing, the order of the pixels that the line sensor 11 has performed vertical scanning and horizontal scanning is
The order of the write addresses of the memories 15R to 15B matches. In addition, as shown in FIG.
The order of the read address of 5B matches the order of scanning of the CRT display. Therefore, an upright image is displayed on the CRT display.

In this case, a read clock RDCK having a frequency f31 (= 1.2 MHz) is supplied to the line sensor 11.
Is supplied to the A / D converter 14, while a signal S66 having a frequency f66 of f66 = N.f31 / (8M) = f31.N / (8M) is supplied as a clock. Therefore, of the image signal S11 for one vertical scan of the line sensor 11, a signal corresponding to N / (8M) pixels is effectively A / D-converted in the A / D converter 14, and the signal R14 is output.
(G14, B14).

Now, since N = 8 and M = 4, the frequency f66 of the signal S66 is f66 = f31.8 / (8.times.4) = f31. (1/4) (= 300 kHz) Becomes Therefore, as shown in the column of FIG. 4, an image pickup signal S11 of 2048 pixels is obtained for each vertical scan of the line sensor 11, and 1/4 (1 for every 3 pixels) among them.
A signal of 512 pixels (pixels) is A / D converted into a signal R14 (or G14, B14).

That is, the number of pixels in the vertical direction is 512 pixels. The number of pixels in the horizontal direction is, for example, 756 according to the number of movements of the film 1 and the number of vertical scans of the line sensor 11.
Pixels.

In this case, the number of pixels in the vertical direction is 512
Although the number of pixels is slightly larger than the number of effective pixels in the vertical direction shown in FIG. 6A, this means that a slightly wider range for the film 1 is read as the effective range. When displaying an image rotated 90 ° in the NTSC system. In this case, N = 11 and M = 6 are set. When the display image is rotated clockwise, the write address to the memories 15R to 15B is decremented by one pixel in the horizontal scanning direction as indicated by an arrow in FIG. 3B, and one horizontal scanning is completed. Each time, the pixel is incremented by one pixel in the vertical scanning direction.

When the displayed image is rotated in the counterclockwise direction, as shown by an arrow in FIG.
The write address for R to 15B is incremented by one pixel in the horizontal scanning direction, and decremented by one pixel in the vertical scanning direction each time one horizontal scanning is completed.

According to such writing, the order of the pixels on which the line sensor 11 has performed vertical scanning and horizontal scanning is
Since the order of the write addresses in the memories 15R to 15B is orthogonal, an image rotated by 90 ° is displayed on the CRT display.

Now, since N = 11 and M = 6, the frequency f66 of the signal S66 is f66 = f31 · 11 / (8 × 6) = f31 · (11/48) (= 275 kHz) Becomes Therefore, as shown in the column of FIG. 4, an image pickup signal S11 of 2048 pixels is obtained for each vertical scan of the line sensor 11, and a signal of 469 pixels which is 11/48 of the signal R11 (signal R14 ( Alternatively, A / D conversion is performed to G14, B14).

That is, the number of pixels in the horizontal direction is 469 pixels. The number of pixels in the vertical direction is, for example, 485 depending on the number of times the film 1 is moved and the line sensor 11 performs vertical scanning.
Pixels.

In FIG. 4, the column (and the column) shows the line sensor 11 rotated by 90 °. This is because the imaging signal S11 from the line sensor 11 is arranged in the order of pixels (partly). It is a model showing that the data is written in the horizontal direction of the memory (though it is decimated as described above),
This does not mean that the line sensor 11 is mechanically rotated by 90 °.

In this case, the number of pixels in the horizontal direction is 469.
Although the number of pixels is smaller than the effective number of pixels in the vertical direction shown in FIG. 6A, this is the case when the frame of film 1 is displayed vertically, such as when the camera is held vertically and photographed on film 1. , So that all of them are displayed. Then, the signals R14 to B14 of the memories 15R to 15B are output.
For example, white pixel data is written in the area where is not written. When displaying an upright image by the PAL method. In this case, N = 10 and M = 4. Also, as indicated by arrows in FIG. 3A, the memories 15R to 15B
Is incremented by one pixel in the vertical scanning direction, and each time one vertical scanning is completed, the writing address is incremented by one pixel in the horizontal scanning direction.

According to such writing, the order of the pixels on which the line sensor 11 has performed vertical scanning and horizontal scanning is
Since the order of the write addresses of the memories 15R to 15B matches, the erect image is displayed on the CRT display.

Now, since N = 10 and M = 4, the frequency f66 of the signal S66 is as follows: f66 = f31 · 10 / (8 × 4) = f31 · (5/16) (= 375 kHz) Becomes Therefore, as shown in the column of FIG. 4, an imaging signal S11 of 2048 pixels is obtained for each vertical scan of the line sensor 11, and a signal of 640 pixels, which is 5/16 of the signal, is converted into a signal R14 ( Alternatively, A / D conversion is performed to G14, B14).

That is, the number of pixels in the vertical direction is 640 pixels. The number of pixels in the horizontal direction is determined by, for example, 739 depending on the movement of the film 1 and the number of vertical scans of the line sensor 11.
Pixels. When displaying an image rotated 90 ° in the PAL system. In this case, N = 9 and M = 5 are set. When the display image is rotated clockwise, the write address to the memories 15R to 15B is decremented by one pixel in the horizontal scanning direction as indicated by an arrow in FIG. 3B, and one horizontal scanning is completed. Each time, the pixel is incremented by one pixel in the vertical scanning direction.

When the displayed image is rotated in the counterclockwise direction, as shown by an arrow in FIG.
The write address for R to 15B is incremented by one pixel in the horizontal scanning direction, and decremented by one pixel in the vertical scanning direction each time one horizontal scanning is completed.

According to such writing, the order of the pixels on which the line sensor 11 has performed vertical scanning and horizontal scanning is
Since the order of the write addresses in the memories 15R to 15B is orthogonal, an image rotated by 90 ° is displayed on the CRT display.

Now, since N = 9 and M = 5, the frequency f66 of the signal S66 is f66 = f31.9 / (8.times.5) = f31. (9/40) (= 270 kHz) Becomes Therefore, as shown in the column of FIG. 4, an imaging signal S11 of 2048 pixels is obtained for each vertical scan of the line sensor 11, and a signal of 461 pixels, which is 9/40, of the signal R14 ( Alternatively, A / D conversion is performed to G14, B14).

That is, the number of pixels in the horizontal direction is 461 pixels. The number of pixels in the vertical direction is, for example, 575, depending on the movement of the film 1 and the number of vertical scans of the line sensor 11.
Pixels.

[0055]

As described above, according to the present invention,
The display of the image on the film 1 is performed. In this case, in particular, according to the present invention, the reading from the memories 15R to 15B is performed only by changing the signals Y18 to B18 to be taken out according to the NTSC system and the PAL system. Therefore, the read address forming circuit can have a simple configuration.

The write addresses to the memories 15R to 15B are changed in the case of the NTSC system, in the case of the PAL system, when displaying an upright image, and when displaying an image rotated by 90 °. However, the writing speed depends on the frequency f66 of the signal S66 in the case of
375 kHz is the highest, and at such a frequency, the processing is easy and the circuit for forming the write address signal does not become expensive. Further, the clock necessary for the write address signal forming circuit can be easily formed by the signal S66.

Further, there is no need to change the CCD line sensor 11 between the NTSC system and the PAL system.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an example of the present invention.

FIG. 2 is a system diagram showing an example of a part of the present invention.

FIG. 3 is a diagram for explaining an order of access to a frame memory.

FIG. 4 is a diagram for explaining an effective number of pixels.

FIG. 5 is a diagram for explaining an order of access to a frame memory.

FIG. 6 is a diagram for explaining a relationship between a screen and the number of pixels.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 read image 2 light source 3 color separation filter 4 imaging lens 11 CCD line sensor 12 gain control amplifier 13 gamma correction amplifier 14 A / D converter 15R to 15B frame memory 16R to 16B lookup table 17R to 17B D / A converter 18 matrix Circuit 20 Microcomputer 21, 23 Driving motor 30 Clock forming circuit 50 Memory controller 61 Phase comparison circuit 62 VCO 63, 66 Variable frequency dividing circuit 64 PLL 65 Frequency dividing circuit

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 9/79 H04N 1/04 H04N 1/387 H04N 5/253 H04N 9/11

Claims (1)

(57) [Claims] A read clock is supplied to a line sensor to perform main scanning on an image to be read, and the line sensor and the image to be read are relatively moved in a direction orthogonal to the direction of the main scanning. The main scanning and sub-scanning are performed to obtain an image signal of the image to be read, and the image signal is supplied to an A / D converter to be A / D converted into a digital signal. An image reading apparatus that reads out the image pickup signal from the memory and outputs a video signal of a predetermined format, and a PLL to which the read clock is supplied, and a frequency division of the output signal of the PLL. The PLL comprises a VCO, and another variable frequency divider for dividing an output signal of the VCO. A phase comparison circuit that compares the phase of the output signal of the variable frequency divider circuit with the read clock and supplies the comparison output to the VCO as a control signal, and divides the output signal of the PLL. An output signal of the variable frequency divider is supplied to the A / D converter as a clock, and a write address signal of the memory is formed from an output signal of the variable frequency divider which divides an output signal of the PLL. The write address signal and the dividing ratio of the two variable frequency dividing circuits are changed in accordance with the format of the output video signal and the direction of the image displayed by the video signal. And supplying a read address signal that changes in accordance with the format of the output video signal to the memory, An image reading device for obtaining a video signal.